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Distance control strategy for deploying content replica servers in an edge cloud

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The Journal of China Universities of Posts and Telecommunications 2019年第2期26卷 91-98页

作者： Wei Feng Zou Weixia Wang Zhen Wu Xiaomei Key Laboratory of Universal Wireless Communications MOEBeijing University of Posts and TelecommunicationsBeijing 100876China Slate Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China Department of Communication Engineering Dalian Neusoft University of InformationDalian 116023China Department of Product and Infrastructure of CTTL-systems China Academy of Information and Communications TechnologyBeijing 100088China

To reduce fetching cost from a remote source,it is natural to cache information near the users who may access the information later.However,with development of 5 G ultra-dense cellular networks andmobile edge computing(MEC),a reasonable selection among edge servers for content delivery becomes a problem when the mobile edge obtaining sufficient replica servers.In order to minimize the total cost accounting for both caching and fetching process,we study the optimal resource allocation for the content replica servers’ deployment.We decompose the total cost as the superposition of cost in several coverages.Particularly,we consider the criterion for determining the coverage of a replica server and formulate the coverage as a tradeoff between caching cost and fetching cost.According to the criterion,a coverage isolation(CI) algorithm is proposed to solve the deployment problem.The numerical results show that the proposed CI algorithm can reduce the cost and obtain a higher tolerance for different centrality indices.

关键词： content delivery network (CDN) MEC replica server deployment minimum cost greedy algorithm

Analysis and Comparison of Time replica and Time Linear Interpolation for Pilot Aided Channel Estimation in OFDM Systems

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International Journal of Communications, Network and System Sciences 2010年第5期3卷 446-452页

作者： Donglin Wang 不详

This paper analyzes and compares two time interpolators, i.e., time replica and time linear interpolator, for pilot aided channel estimation in orthogonal frequency division multiplexing (OFDM) systems. The mean square error (MSE) of two interpolators is theoretically derived for the general case. The equally spaced pilot arrangement is proposed as a special platform for these two time interpolators. Based on this proposed platform, the MSE of two time interpolators at the virtual pilot tones is derived analytically;moreover, the MSE of per channel estimator at the entire OFDM symbol based on per time interpolator is also derived. The effectiveness of the theoretical analysis is demonstrated by numerical simulation in both the time-invariant frequency-selective channel and the time varying frequency-selective channel.

关键词： OFDM Channel Estimation Time replica Time Linear Interpolation Virtual Pilots

A CORBA replication Voting Mechanism for Maintaining the replica Consistent

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Journal of Software Engineering and Applications 2009年第4期2卷 276-282页

作者： Guohua WU Xiaojun LI Qiuhua ZHENG Zhen ZHANG 不详

Nowadays, more and more applications are being developed through distributed object computing middleware, such as CORBA, their requirements for fault-tolerance, especially real time and critical system, become more and more critical. Despite almost ten years have passed since the earliest FT-CORBA standard was promulgated by Object Management Group (OMG), CORBA is still facing many challenges when it is used for distributed applications developing, as the standard is complex and lack of understanding. This paper focus on the consistency of the replicated object and the network partition problem, it incorporates a CORBA replication Voting Mechanism (CRVM) to meet the challenge which makes a good performance.

关键词： distributed computing CRVM fault-tolerance replica consistent networking partition

PRS:Predication-Based replica Selection Algorithm for Key-Value Stores

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国际计算机前沿大会会议论文集 2017年第1期 79-81页

作者： Liyuan Fang Xiangqian Zhou Haiming Xie Wanchun Jiang School of Information Science and Engineering Central South UniversityChangsha 410083HunanChina

The tail latency of end-user requests,which directly impacts the user experience and the revenue,is highly related to its corresponding numerous accesses in key-value stores.The replica selection algorithm is crucial to cut the tail latency of these key-value accesses.Recently,the C3 algorithm,which creatively piggybacks the queue-size of waiting keys from replica servers for the replica selection at clients,is proposed in NSDI 2015.Although C3 improves the tail latency a lot,it suffers from the timeliness issue on the feedback information,which directly influences the replica selection.In this paper,we analysis the evaluation of queuesize of waiting keys of C3,and some findings of queue-size variation were made.It motivate us to propose the Prediction-Based replica Selection(PRS)algorithm,which predicts the queue-size at replica servers under the poor timeliness condition,instead of utilizing the exponentially weighted moving average of the state piggybacked queue-size as in C3.Consequently,PRS can obtain more accurate queue-size at clients than C3,and thus outperforms C3 in terms of cutting the tail latency.Simulation results confirm the advantage of PRS over C3.

关键词： Prediction replica selection Tail-latency Key-value stores

Studies on Artificial replica of Eperythrozoonosis

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Journal of Shanghai Jiaotong university(Science) 2005年第S1期10卷 92-96页

作者：华修国崔立朱建国严亚贤朱淑文姚从斌 School of Agriculture and Biology Shanghai Jiaotong Univ. Shanghai 201101 China

Twenty one health hybrid dogs weighted （7±3.2） kg were intramuscularly injected with tetracyclinum in a dose of 10 mg/kg body weight for continuous 5 days while the blood eperythrozoon test showing negative reaction and divided randomly into three groups. The treating methods were respectively GroupⅠ, lienectomy, Group Ⅱ, both lienectomy and injection of immunosuppressor and Group Ⅲ, control. All dogs were intraperitoneal injected with 4ml anticoagulative blood from dog with eperythrozoonosis (the erythrozoon infection rate was 94 %, erythrocyte was 3.8×106/mm3). The result shown the eperythrozoon infection rate in GroupⅠ and Ⅱ were respectively 1.5 % and 2.1 % on the first day after administration. On the sixth day, the infection rate of GroupⅠ, Ⅱ and Ⅲ were 81.3 %, 86.5 % and 75.2 % respectively. The hematological changes in GroupⅠ and Ⅱ included both decrease in packed cell volume （HCT PCV）, hemoglobin, total erythrocyte, acidocyte number and lymphocyte, and rise in total leukocyte, neutrocyte and monocyte. Five dogs in GroupⅠ and seven dogs in Group Ⅱ showed apparent symptoms of anaemia, icterus, high fever, anorexia, diarrhea and emesis,etc. The morbidity in GroupⅠ and Ⅱ were respectively 71 % and 100 %, and two dogs in Group Ⅱdied. The changes in clinical symptoms, the hemogram and the physiological indexes in GroupⅠ and Ⅱ were the same as those in natural eperythrozoonosis.

关键词： eperythrozoonosis asrtificial replica lienectomy immunosuppressor

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网格环境下基于多replica的数据传输

计算机工程 2007年第1期33卷 44-46页

作者：应益峰宋广华浙江大学计算机学院

数据密集型应用需要在广域、分布式计算环境中高效地传输大量的信息。提出了一种在网格环境下基于多replica的并行传输方法来实现GridFtp中的条状传输,以提高网络传输的效率及其安全性,并实现了一个适用于网格环境的数据传输客户端工具(... 详细信息

数据密集型应用需要在广域、分布式计算环境中高效地传输大量的信息。提出了一种在网格环境下基于多replica的并行传输方法来实现GridFtp中的条状传输,以提高网络传输的效率及其安全性,并实现了一个适用于网格环境的数据传输客户端工具(MFTP)。实验表明,MFTP具有较好的数据传输性能和可靠性。

关键词： GridFTP replica 条状传输

The "replica of Marco Polo's Will" is Donated to WTA

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China & The World Cultural Exchange 2021年第10期87卷 34-35页

作者： An Sheng 不详

The donation of the"replica of Marco Polo's Will"opens the comprehensive cooperation between the two countries in China-Italy Year of Culture and Tourism.More than 700 years ago,Marco Polo came to Hangzhou,China from Ven ice,Italy.His Travels of Marco Polo built a bridge to promote cultural exchanges between the East and the West;Today,in the 21 st century.

关键词： Marco replica exchanges

Multi-bit soft error tolerable L1 data cache based on characteristic of data value

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Journal of Central South University 2015年第5期22卷 1769-1775页

作者：王党辉刘合朋陈怡然 School of Computer Science Northwestern Polytechnical University Department of Electrical and Computer Engineering University of Pittsburgh

Due to continuous decreasing feature size and increasing device density, on-chip caches have been becoming susceptible to single event upsets, which will result in multi-bit soft errors. The increasing rate of multi-bit errors could result in high risk of data corruption and even application program crashing. Traditionally, L1 D-caches have been protected from soft errors using simple parity to detect errors, and recover errors by reading correct data from L2 cache, which will induce performance penalty. This work proposes to exploit the redundancy based on the characteristic of data values. In the case of a small data value, the replica is stored in the upper half of the word. The replica of a big data value is stored in a dedicated cache line, which will sacrifice some capacity of the data cache. Experiment results show that the reliability of L1 D-cache has been improved by 65% at the cost of 1% in performance.

关键词： data cache reliability replica data value single event upset(SEU)

Fabrication of Self-cleaning Antireflective Polymer Surfaces by Mimicking Underside Leaf Hierarchical Surface Structures

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Journal of Bionic Engineering 2019年第3期16卷 400-409页

作者： Srinadh Mattaparthi Chandra Shekhar Sharma Creative & Advanced Research Based on Nanomaterials (CARBON) Laboratory Department of Chemical Engineerings Indian Institute of Technology Hyderabad Kandi Telangana 502285 India

In this work, we utilized underside of four different plant leaves with different scale of hierarchical surface roughness to fabricate large area self-cleaning antireflective polymer surfaces. A simple and precise two-step soft-lithography replica molding technique was deployed by using polydimethylsiloxane (PDMS) polymer as a replicating material. In the first step, a negative PDMS replica was fabricated by using the underside of an original leaf as a template material. In the second step, a positive PDMS replica was fabricated through a negative PDMS replica used as a template. In order to study the non-wetting and light trapping properties, as-replicated polymer surfaces were characterized using Scanning Electron Microscopy (SEM), contact angle goniometer, and UV-Vis spectroscopy. SEM images confirmed the successful replication of complex hierarchical structures while contact angle measurement studies established retaining high non-wetting properties in polymer replicas. Optical studies suggest near zero reflection in normal mode and less than 5% diffuse reflection when measured using integrated sphere mode. These results have been correlated and explained with the air-liquid fraction and roughness factor as measured using three-dimensional optical profilometer.

关键词： biomimicking natural leaf replica molding non-wetting light trapping hierarchical roughness